Ok, I know this is caused by interference between the switch-mode converters in these wizz-bang new 240V lighting units, but what's the simplest way to stop it?
Also, it is likely to be frequency-dependent impedance variations, or leaking of the actual switching frequency onto the wiring between the units? In other words, is a ferrite clamp or power-line filter likely to help?
The dimmers are Lumex LoadSmart LED Dimmer, LT1D459LS series. The LEDS are Atom AT9039. The circuit most affected has four LEDS. The circuit with 2 doesn't seem to do it (not readily anyhow), and the five-LED one seems less susceptible.